1. Field of the Invention
The present invention relates to a liquid crystal display (LCD) panel, particularly a vertical alignment (VA) liquid crystal display panel, which does not include a protrusion and is accordingly without a light leakage occurring at an edge of the protrusion.
2. Description of the Prior Art
LCD devices have been widely used in various electronic devices, such as mobile phones, personal digital assistants (PDA), notebooks, terminals, television sets, becoming a main display product in the market. However, the view angle of the conventional LCD is limited by the structure of the liquid crystal molecule and the optical character. Thus, it is necessary to develop a LCD with wider view angle, such as a vertical alignment liquid crystal display (VALCD) panel.
Please refer to FIG. 1, a schematic plan view of a conventional VALCD panel and a cross-sectional schematic diagram of the LCD panel along the line AA′. As shown in FIG. 1, a sub-pixel area 10 of a conventional VALCD panel includes a first substrate 12, a second substrate 14, a liquid crystal layer 16 filled between the first substrate 12 and the second substrate 14, a common electrode 18 positioned on the first substrate 12 on the side facing to the second substrate 14, a transparent electrode 20 disposed between the liquid crystal layer 16 and the second substrate 14, protrusions 22 disposed on the common electrode 18 on the side facing to the second substrate 14. The sub-pixel area is divided into multi-domains through the settlement of the protrusions 22. The liquid crystal molecules of each domain are aligned in various directions and rotate, respectively, increasing the view angle of VALCD panel 10.
As it is described in the above, although the conventional VALCD panel has wider view angle, due to the protrusions, some liquid crystal molecules slightly tilt without a voltage applied to. Therefore, a light leakage tends to occur at the position 24 or 26 beside the protrusions 22. Accordingly the contrast ratio for the display is decreased and the display performance is affected.
Please refer to FIG. 2, a schematic plan view of another conventional vertical alignment LCD panel which is a modification from the above-mentioned VALCD panel. A transparent conductive layer 32 having fine slits 34 and protrusions 36 are comprised. The alignment of liquid crystal is stable, but in the gray scale display, the display image is not uniform and irregular shapes appear. The pattern of such transparent conductive layer having fine slits is defined by photolithography. It is not easy to control the uniformity of the resist thickness during the manufacture, and accordingly the slit widths are not constant, such that an irregular shape of mura occurs when the display is operated. Furthermore, the liquid crystal arrangement at the edge of the pixel in the vicinity of data lines is not stable, due to the electric field from the data lines.
Therefore, a VALCD panel having a better structure is still needed to allow a stable liquid crystal arrangement and avoid light leakage and mura effect.